The present disclosure relates to a speed change device.
Conventionally, for this type of speed change device, a speed change device including a planetary gear mechanism, which includes a sun gear, a ring gear, a plurality of pinion gears, and a carrier; and a brake that is disposed on an outer circumferential side of the planetary gear mechanism and that can hold the carrier stationary to a case (for example, see Japanese Patent Application Publication No. 2013-96559 and Japanese Patent Application Publication No. H2-146343) has been proposed.
In the speed change device described in Japanese Patent Application Publication No. 2013-96559, a brake hub of the brake includes an outer circumferential portion having a cylindrical shape that surrounds the outer circumferential side of the ring gear, and an inner circumferential portion that extends toward a radially inner side from one end in an axial direction of the outer circumferential portion. Furthermore, an oil hole, through which lubricating oil passes, is formed on the ring gear and the outer circumferential portion of the brake hub. Furthermore, each pinion gear is rotatably supported by the carrier and the inner circumferential portion of the brake hub. With this configuration, the lubricating oil inside the planetary gear mechanism is supplied to the brake through the oil hole, thereby causing lubrication and cooling of the brake to be carried out.
In the speed change device described in Japanese Patent Application Publication No. H2-146343, the brake hub of the brake includes an outer circumferential portion in a cylindrical shape that surrounds the outer circumferential side of the ring gear, and an inner circumferential portion that extends toward a radially inner side from one end in an axial direction of the outer circumferential portion. The carrier includes a carrier main body and a carrier cover. The carrier main body includes a planar portion that supports one end of a pinion shaft inserted to each pinion gear, a plurality of leg portions extending in the axial direction at intervals in the circumferential direction from the outer circumference of the planar portion, and a connecting portion that connects the planar portion and the leg portions. The carrier cover is fixed to the plurality of leg portions and supports the other end of each of the pinion shafts. Furthermore, a portion between the two adjacent leg portions in the outer circumference of the planar portion of the carrier main body and the inner circumference of the inner circumferential portion of the brake hub are fixed, where a space is formed between the outer circumferential surface of the connecting portion of the carrier main body and the inner circumferential surface of the inner circumferential portion of the brake hub.